/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.hive.ql.parse;

import java.io.PrintStream;
import java.io.Serializable;
import java.util.HashMap;
import org.apache.hadoop.hive.ql.exec.Operator;
import org.apache.hadoop.hive.ql.lib.Node;
import org.apache.hadoop.hive.ql.lib.NodeProcessor;
import org.apache.hadoop.hive.ql.lib.NodeProcessorCtx;

public class PrintOpTreeProcessor implements NodeProcessor {
  
  private PrintStream out;
  private HashMap<Operator<? extends Serializable>, Integer> opMap = new HashMap<Operator<? extends Serializable>, Integer>();
  private Integer curNum = 0;

  public PrintOpTreeProcessor() {
    out = System.out;
  }
  
  public PrintOpTreeProcessor(PrintStream o) {
    out = o;
  }
  
  private String getParents(Operator<? extends Serializable> op) {
    StringBuilder ret = new StringBuilder("[");
    boolean first = true;
    if(op.getParentOperators() != null) {
      for(Operator<? extends Serializable> parent :  op.getParentOperators()) {
        if(!first)
          ret.append(",");
        ret.append(opMap.get(parent));
        first = false;
      }
    }
    ret.append("]");
    return ret.toString();
  }
  
  private String getChildren(Operator<? extends Serializable> op) {
    StringBuilder ret = new StringBuilder("[");
    boolean first = true;
    if(op.getChildOperators() != null) {
      for(Operator<? extends Serializable> child :  op.getChildOperators()) {
        if(!first)
          ret.append(",");
        ret.append(opMap.get(child));
        first = false;
      }
    }
    ret.append("]");
    return ret.toString();
  }
  
  public Object process(Node nd, NodeProcessorCtx ctx, Object... nodeOutputs) throws SemanticException {
    Operator<? extends Serializable> op = (Operator<? extends Serializable>)nd;
    if (opMap.get(op) == null) {
      opMap.put(op, curNum++);
    }
    out.println("[" + opMap.get(op) + "] " + op.getClass().getName() + " =p=> " + getParents(op) + " =c=> " + getChildren(op));
    if(op.getConf() == null) {
      return null;
    }
    return null;
  }
}
